Testing Electronic Thermostats

Is there a way to test Electronic thermostats? I just installed a GQF brand Multi-turn thermostat in my incubator and it heats 100% of the time!!! It will not cycle off and on like it is supposed to. I would like to make sure its the thermostat itself causing the problem and not my wiring before I pull it out and send it back to GQF. It has 3 Wires if that makes a difference.